兔圆小囊及肠道组织中抗菌肽的免疫组织化学和免疫电镜细胞化学定位

采用免疫组织化学和免疫电镜细胞化学技术观察了兔圆小囊及其他肠道组织中产抗菌肽细胞的分布定位。免疫组织化学观察发现,产抗菌肽细胞在兔圆小囊的黏膜上皮、圆顶上皮以及淋巴组织的滤泡生发中心、圆顶区和帽区均有分布;在兔感染多杀性巴氏杆菌后,圆小囊及其他肠道组织中的抗菌肽免疫组织化学阳性细胞数量明显增多,阳性反应增强。免疫电镜细胞化学观察结果显示,除肠道黏膜上皮细胞、异嗜性白细胞、巨噬细胞中存在抗菌肽免疫组织化学阳性反应信号外,在淋巴细胞内也发现阳性反应信号,尤其是在圆小囊淋巴组织中的DNES细胞内发现抗菌肽免疫组织化学阳性反应信号。表明圆小囊的DNES细胞和淋巴细胞均可产生抗菌肽。     

Effects of dendritic cell stimulation on cytotoxic activity of cord blood derived cytokine-induced killer cells,natural killer cells and CD45RO expression in CIK cells

AIM: To investigate the efficacy of dendritic cells (DCs) that augments the cytotoxic activity of cytokine-induced killer (CIK) cells, natural killer (NK) cells from a same donor and the CD45RO expression on CIK cells. METHODS: The expanded killer cells were divided into two groups: group A was pre-cocultured with DCs for 6 days, group B was the control that without any stimulation. Cytotoxicity of CIK and NK cells was measured at different effect-target ratio against K562 and HL-60. CD45RO and CD45RA expression on CIK cells in different groups were detected by flow cytometry. RESULTS: Cytotoxicity of CB derived killer cells was positive correlation with effect-target ratio. The cytotoxicity of group A against HL-60 was higher than that of group B significantly. At 20∶1 effector-target ratio, the lytic activity of group A CIK, NK cells against K562 was higher than that of group B significantly, but no significant difference between them at 10∶1 effector-target ratio. The CD45RO expression on CIK cells in groups A was significantly higher than that in groups B. CONCLUSION: CIK and NK cells cocultured with DCs can augment the killer's cytotoxicity against tumor cells and promote the CD45RO expression on CIK cells.     

Structure,receptor and pathophysiological function of natriuretic peptide

Five natriuretic peptides (NP) have been identified: A-type, B-type, C-type, D-type and V-type. All of them have ringed-structures. The actions of the natriuretic peptides are modulated through their cognate receptors, which are named as NPR-A, NPR-B and NPR-C. The receptors are involved in the cGMP-dependent signaling cascades, which take part in many different physiological regulation, such as diureses, vasodilatation, depressing blood pressure, improving immunity, promoting development of bone, regulating nerve system and so on. At present, ANP and BNP have become a marker in diagnostic some cardiovascular diseases.     

Insights into the Influence of Signal Peptide on the Enzymatic Properties of Alginate Lyase AlyI1 with Removal Effect on Pseudomonas aeruginosa Biofilm

Most reports on signal peptides focus on their ability to affect the normal folding of proteins, thereby affecting their secreted expression, while few studies on its effects on enzymatic properties were published. Therefore, biochemical characterization and comparison of alginate lyase rALYI1/rALYI1-1 (rALYI1: without signal peptides; rALYI1-1:with signal peptides) were conducted in our study, and the results showed that the signal peptide affected the biochemical properties, especially in temperature and pH. rALYI1 (32.15 kDa) belonging to polysaccharide lyase family 7 was cloned from sea-cucumber-gut bacterium Tamlana sp. I1. The optimum temperature of both rALYI1 and rALYI1-1 was 40 °C, but the former had a wider optimum temperature range and better thermal stability. The optimum pH of rALYI1 and rALYI1-1 were 7.6 and 8.6, respectively. The former was more stable and acid resistant. Noticeably, rALYI1 was a salt-activated enzyme and displayed remarkable salt tolerance. Alginate, an essential polysaccharide in algae and Pseudomonas aeruginosa biofilms, is composed of α-L-guluronate and β-D-mannuronate. It is also found in our study that rALYI1 is also effective in removing mature biofilms compared with controls. In conclusion, the signal peptide affects several biochemical properties of the enzyme, and alginate lyase rALYI1 may be an effective method for inhibiting biofilm formation of Pseudomonas aeruginosa.     

抗菌肽及其基因表达体系研究进展

抗菌肽是上个世纪70年代由瑞典科学家Boman H G首次发现的,其具有优良的光谱抗菌性能,无残留,不会导致耐药菌株的出现,是目前抗生素类较有潜力的替代品。早在上世纪80年代,人们就试图通过转基因等生物工程技术改良物种或大量表达该类物质,目前已有众多的表达体系和转基因动植物研究成功,并有一些抗菌肽类药物投入临床使用。文中综述了近年来国内外关于抗菌肽的分离提取、体外表达和转基因动植物技术,主要论述该物质在基因和生物工程方面研究进展,从而为其规模化生产利用提供参考和借鉴。     

重组猪蛔虫抗菌肽cecropin P1在毕赤酵母中的表达及抑菌活性

根据已发表的蛔虫抗菌肽cecropin P1基因编码序列设计引物,采用RT-PCR方法从猪肠道蛔虫中扩增出cecropin P1基因,并将其插入到酵母分泌型表达载体pPIC9K中α-因子信号肽下游的SnaBⅠ和NotⅠ位点之间,构建成cecropin P1基因的酵母分泌型表达载体pPIC9K/cecropin P1。载体经SalⅠ酶切线性化,电转化到组氨酸缺陷型的酵母宿主菌GS115中,然后利用以葡萄糖为碳源的培养基（MD）和以甲醇为碳源的培养基（MM）筛选出组氨酸His＋型和甲醇利用正型（Mut＋）酵母重组体,再经G418加压筛选得到高拷贝cecropin P1基因的重组酵母。经PCR检测证明cecropin P1基因已整合到毕赤酵母的染色体中。重组酵母经摇瓶发酵培养和甲醇诱导,通过Tricine-SDS-PAGE检测,重组酵母能够分泌表达重组cecropin P1,同时表达的cecropin P1对大肠杆菌和金黄色葡萄球菌均有明显的抑菌活性。     

Advances in the expression of killer cell inhibitory receptors by T cells

Only in recent years, attentions have been drawn to the significance of expressing killer cell inhibitory receptors (KIR) in T cells KIRs specifical y bind to the corresponding region of the MHC class Imolecules and transmit negative signals to prevent cytotoxity of T cells. When the ligands of KIRs are missing, the lysis of the target cells can't be avoided.Perhaps the existence of KIRs is the main mechanism for preventing T cells from attacking autologous tissues. The recognition mechanism of the interaction between the KIR⁺ donor T cells and the recipient's MHC class I molecule expressing tissue cel s might shed light on the establishment of the immunotolerance for the prevention of allo-graft reject ion and graft-versus-host disease.     

伪狂犬病病毒闽A株糖蛋白gD基因去信号肽片段在大肠埃希氏菌中的表达

应用PCR方法从包含伪狂犬病病毒（PRV）Fa株糖蛋白gD基因的重组质粒pB13中扩增出糖蛋白gD基因去信号肽片段，将其克隆到大肠埃希氏菌表达载体pThiohisA中。测序结果表明，糖蛋白gD基因去信号肽片段长1155bp，与PRVFa株糖蛋白gD基因完全一致。经1mmol／L IPTG诱导后，重组质粒pThiohisA-gD在大肠埃希氏 菌XL1-blue、Top10、DE3和DH5a中均得到表达，其中在宿主菌XL 1-blue中表达量最高。Western-blotting结果显示，大肠埃希氏菌XL1-blue表达的糖蛋白gD具有免疫原性。     

饲粮添加酶解蛋白肽对断奶仔猪生长性能、血清免疫指标和肠道菌群的影响

本试验旨在探究饲粮添加酶解蛋白肽对断奶仔猪生长性能、血清免疫指标和肠道菌群的影响,以确定断奶仔猪饲粮中酶解蛋白肽的适宜添加水平。试验选取150头21日龄体重为(7.01±0.17) kg的健康“杜×长×大”三元杂交断奶仔猪,随机分为5个组,每组5个重复,每个重复6头(公母各占1/2)。各组断奶仔猪分别饲喂在基础饲粮中添加0(对照组)、2%、4%、6%和8%酶解蛋白肽的等氮等能饲粮。试验共35 d,其中预试期7 d、正试期28 d。结果表明：1)与对照组相比,饲粮添加6%和8%酶解蛋白肽极显著提高各阶段断奶仔猪平均日采食量和平均日增重(P<0.01),极显著降低第1～14天和第1～28天腹泻率(P<0.01),显著降低第15～28天料重比(P<0.05);饲粮添加6%酶解蛋白肽极显著降低断奶仔猪第15～28天腹泻率(P<0.01),显著降低第1～14天和第1～28天料重比(P<0.05)。2)试验第14天,与对照组相比,饲粮添加2%～6%酶解蛋白肽极显著提高断奶仔猪血清免疫球蛋白G(IgG)含量(P<0.01),饲粮添加2%、4%和8%酶解蛋白肽极显著...